diff --git a/drivers/ide/arm/rapide.c b/drivers/ide/arm/rapide.c
index e6b56d1..b5b6ed8 100644
--- a/drivers/ide/arm/rapide.c
+++ b/drivers/ide/arm/rapide.c
@@ -78,8 +78,8 @@
 
 	ecard_set_drvdata(ec, NULL);
 
-	/* there must be a better way */
-	ide_unregister(hwif - ide_hwifs);
+	ide_unregister(hwif->index);
+
 	ecard_release_resources(ec);
 }
 
diff --git a/drivers/ide/mips/au1xxx-ide.c b/drivers/ide/mips/au1xxx-ide.c
index b00c71f..71782b3 100644
--- a/drivers/ide/mips/au1xxx-ide.c
+++ b/drivers/ide/mips/au1xxx-ide.c
@@ -691,7 +691,7 @@
 	ide_hwif_t *hwif = dev_get_drvdata(dev);
 	_auide_hwif *ahwif = &auide_hwif;
 
-	ide_unregister(hwif - ide_hwifs);
+	ide_unregister(hwif->index);
 
 	iounmap((void *)ahwif->regbase);